1. Field of the Invention
The present invention relates to a container assembly having a support bridge that is capable of preventing collapse of the container during centrifugation. A lid is positioned on top of the container, and the support bridge is disposed between the lid and an upper portion of the container.
2. Description of the Prior Art
A centrifuge instrument is a device by which liquid samples may be subjected to a centrifugal force. Swinging bucket centrifuge systems are well known in the centrifuge art. The rotor in such a system is adapted to receive a bucket that hangs from the rotor body. When the rotor is at rest, the bucket hangs in a generally vertical position. When the rotor is accelerated, the bucket swings from its rest position to a horizontal position.
U.S. Pat. No. 5,591,114 to Romanauskas, which is incorporated herein by reference, discloses a swinging bucket centrifuge rotor. The body of the rotor has at least one pair of confronting planar sidewalls that are circumferentially spaced apart to define a generally axially extending slot. Each planar sidewall has a trunnion pin mounted thereon, and the trunnion pins as a pair serve to receive a swinging bucket.
U.S. Pat. No. 5,624,370 to Romanauskas, which is incorporated herein by reference, discloses a bucket for use in a swinging bucket centrifuge rotor. The bucket has a cylindrical body with a pair of planar abutments formed on the body. The abutments are diametrically disposed on the body. A slot is formed between each abutment and a portion of the body of the bucket, and each slot has a groove. The bucket is installed on a rotor by lowering the bucket onto a pair of rotor trunnion pins such that each trunnion pin is received within a groove defined on a respective abutment.
A container for use in a swinging bucket centrifuge system and made of a rigid material is generally cylindrical in form. However, a swinging bucket can also define a generally rectangular volume within which a flexible or non-cylindrical container can be held. Such an arrangement is commonly used for holding blood bags for centrifugation of blood.
The centrifugal force that advantageously serves to separate a liquid sample into its constituent parts also acts upon the container that holds the sample. The container must be capable of withstanding this force otherwise it will be disfigured or destroyed. For example, if a blood bag is not substantially full during centrifugation, the unfilled portion of the bag will crease and fold into the remainder of the bag and blood particles can become lodged in a crease. Even in the case of a more rigid container, the structural integrity of the container must be sufficient to ensure that it does not collapse under the stress of centrifugal force.
In the prior art, the integrity of a container held within a swinging bucket is maintained by either substantially filling the container or by reinforcing the walls of the container. Filling a container is a problem in the case where an operator wishes to work with a sample volume that is less than the amount required to fill the container. On the other hand, reinforcing the walls of a container requires the use of a material that is thicker or stronger than the material used for a non-reinforced container. Consequently, a container with reinforced walls is heavier, less transparent, has a reduced volume capacity and is more expensive than a non-reinforced container. Furthermore, such a container cannot be made by an inexpensive manufacturing process such as blow molding.
There is a need for a lightweight, inexpensive container assembly that does not collapse when subjected to centrifugal force.
There is also a need for such a container assembly that accommodates a flexible or non-cylindrical container.
A container assembly comprising a container housing, a lid for sealing the container housing, and a support bridge positioned below the lid and about the neck of the container housing, thereby preventing centrifugal forces acting on the lid, and on the neck and shoulder of the container, from collapsing the container during centrifugation. To secure its position, the support bridge, in one embodiment of the invention, has an aperture for securing the lid and a counter bore defining a flange that engages an edge of the lid. A lip formed at either end of the bridge engages a respective edge of a swinging bucket in which the container is disposed during centrifugation.
It will be noted, as the description of one embodiment herein proceeds, that the container includes a chamber that can have a non-cylindrical form. In an alternate embodiment, the chamber can be a bag.
It will especially be appreciated by those skilled in the art that the present invention permits the use of a container made of an inexpensive, lightweight material.